“There’s a whole light show going on down there, and people never see it.”

A green biofluorescent chain catshark (Scyliorhinus retifer). Scientists already knew that some marine organisms fluoresce, including corals and jellyfish, but the NSF-funded study, The Covert World of Biofluorescence is the first reported evidence of widespread biofluorescence among fishes.

With the help of blue light and special long-pass filters, scientists have uncovered more of the undersea world’s secrets. A study published today describes more than 180 species of marine fishes that glow in different colors and patterns, via a process known as biofluorescence.

Scientists already knew that some marine organisms fluoresce, including corals and jellyfish, but this is the first reported evidence of widespread biofluorescence among fishes.